Leaflet-Cuff Attachments for Prosthetic Heart Valve

ABSTRACT

A prosthetic heart valve includes a stent having a collapsed condition and an expanded condition, the stent having a proximal end, a distal end and a plurality of commissure features. The heart valve further includes a valve assembly secured to the stent, the valve assembly including a cuff and a plurality of leaflets, each of the leaflets having a free edge having a first end and a second end, and a second edge secured to the cuff, the second edge having a first end, a second end, a first folded portion adjacent the first end, a second folded portion adjacent the second end, and an unfolded portion between the first and second folded portions. The first and second folded portions couple the leaflet to ones of the commissure features.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of the filing date of U.S.Provisional Patent Application No. 61/918,305 filed Dec. 19, 2013, thedisclosure of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to heart valve replacement and, inparticular, to collapsible prosthetic heart valves. More particularly,the present invention relates to collapsible prosthetic heart valveshaving unique valve leaflet attachments.

Prosthetic heart valves that are collapsible to a relatively smallcircumferential size can be delivered into a patient less invasivelythan valves that are not collapsible. For example, a collapsible valvemay be delivered into a patient via a tube-like delivery apparatus suchas a catheter, a trocar, a laparoscopic instrument, or the like. Thiscollapsibility can avoid the need for a more invasive procedure such asfull open-chest, open-heart surgery.

Collapsible prosthetic heart valves typically take the form of a valvestructure mounted on a stent. There are two common types of stents onwhich the valve structures are ordinarily mounted: a self-expandingstent and a balloon-expandable stent. To place such valves into adelivery apparatus and ultimately into a patient, the valve may first becollapsed or crimped to reduce its circumferential size and diameter.

When a collapsed prosthetic valve has reached the desired implant sitein the patient (e.g., at or near the annulus of the patient's heartvalve that is to be replaced by the prosthetic valve), the prostheticvalve can be deployed or released from the delivery apparatus andre-expanded to full operating use range. For balloon-expandable valves,this generally involves releasing the entire valve, assuring its properlocation, and then expanding a balloon positioned within the valvestent. For self-expanding valves, on the other hand, the stentautomatically expands as the sheath covering the valve is withdrawn.

BRIEF SUMMARY OF THE INVENTION

In some embodiments, a prosthetic heart valve includes a stent having acollapsed condition and an expanded condition, the stent having aproximal end, a distal end and a plurality of commissure features. Theheart valve further includes a valve assembly secured to the stent, thevalve assembly including a cuff and a plurality of leaflets, each of theleaflets having a free edge having a first end and a second end, and asecond edge secured to the cuff, the second edge having a first end, asecond end, a first folded portion adjacent the first end, a secondfolded portion adjacent the second end, and an unfolded portion betweenthe first and second folded portions. The first and second foldedportions couple the leaflet to ones of the commissure features.

In some embodiments, a prosthetic valve assembly includes asubstantially cylindrical cuff, a plurality of leaflets disposed insidethe cuff, a reverse-running stitch coupled to unfolded portions of eachof the leaflets, the reverse-running stitch having an outer partdisposed between the cuff and each of the leaflets and an inner partdisposed on an opposite side of each of the leaflets and a suture forcoupling the cuff to each of the leaflets.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention are disclosed herein withreference to the drawings, wherein:

FIG. 1A is a partial side view of a prosthetic heart valve showing apotential strain distribution profile in the valve assembly;

FIG. 1B is an enlarged partial view of the prosthetic heart valve ofFIG. 1A showing the strain distribution in the leaflet;

FIG. 2A is a highly schematic cross-sectional view of a portion of acollapsible prosthetic heart valve according to the present inventionhaving folded leaflets sutured to the cuff;

FIG. 2B is an enlarged side view of a portion of a collapsibleprosthetic heart valve according to the present invention showing afolded belly flap;

FIG. 3 is a partial developed view of a collapsible prosthetic heartvalve according to the present invention showing the suturing pattern ofthe leaflets to the cuff;

FIG. 4 is an enlarged side view of a portion of the collapsibleprosthetic heart valve of FIG. 3 showing the runner region betweenancons;

FIGS. 5A and 5B are side views of a collapsible prosthetic heart valveaccording to the present invention having a tissue pocket between thecuff and the leaflet, and a prior art device lacking such a pocket,respectively;

FIG. 6 is a partial side view of a prosthetic heart valve showing theleaflet-cuff attachment load distribution in the valve assembly;

FIG. 7A is a highly schematic perspective view of an underwire securedto a cuff;

FIG. 7B is a highly schematic top view of an underwire secured to acuff;

FIG. 8 is a side view of a collapsible prosthetic heart valve having anunderwire;

FIG. 9A is a side view of another collapsible prosthetic heart valvehaving an underwire;

FIG. 9B is an enlarged side view of a portion of the collapsibleprosthetic heart valve of FIG. 9A showing the underwire crossing struts;

FIG. 10A is a highly schematic cross-sectional view of a portion of acollapsible prosthetic heart valve according to the present inventionhaving a folded leaflet sutured to the underwire and the cuff;

FIG. 10B is a highly schematic cross-sectional view of a portion ofanother collapsible prosthetic heart valve according to the presentinvention having a folded leaflet sutured to the underwire and the cuff;

FIG. 10C is a highly schematic cross-sectional view of a portion of afurther collapsible prosthetic heart valve according to the presentinvention having a folded leaflet sutured to the underwire and the cuff;

FIG. 11A is a side view of a leaflet folded over itself to produce abelly flap and secured via a reverse-running stitch;

FIG. 11B is a highly schematic cross-sectional view of a portion of afurther collapsible prosthetic heart valve according to the presentinvention having a folded leaflet sutured to the underwire and the cuffthrough a reverse-running stitch;

FIGS. 11C-P are highly schematic cross-sectional views of variousconfigurations of attaching an underwire to a cuff;

FIG. 12 is a side view of a leaflet having folded portions and anunfolded belly region including a reverse-running stitch;

FIGS. 13A-K are highly schematic cross-sectional views of variousconfigurations of attaching an underwire to an unfolded leaflet and acuff;

FIG. 14 is a side view of a leaflet having folded portions and anunfolded belly region including a diamond-shaped reverse-running stitch;

FIG. 15 is a side view of a leaflet having folded portions and anunfolded belly region including a pair of parabolic reverse-runningstitches;

FIG. 16 is a side view of a leaflet having folded portions and anunfolded belly region including a rectangular-shaped reverse-runningstitch; and

FIG. 17 is a side view of a leaflet having folded portions and anunfolded belly region including a triangle-shaped reverse-runningstitch.

Various embodiments of the present invention will now be described withreference to the appended drawings. It is to be appreciated that thesedrawings depict only some embodiments of the invention and are thereforenot to be considered limiting of its scope.

DETAILED DESCRIPTION

As used herein, the term “proximal,” when used in connection with aprosthetic heart valve, refers to the end of the heart valve closest tothe heart when the heart valve is implanted in a patient, whereas theterm “distal,” when used in connection with a prosthetic heart valve,refers to the end of the heart valve farthest from the heart when theheart valve is implanted in a patient. When used in connection withdevices for delivering a prosthetic heart valve into a patient, theterms “proximal” and “distal” are to be taken as relative to the user ofthe delivery devices. “Proximal” is to be understood as relatively closeto the user, and “distal” is to be understood as relatively farther awayfrom the user. Also, as used herein, the words “substantially,”“generally” and “about” are intended to mean that slight variations fromabsolute are included within the scope of the structure or processrecited.

FIG. 1A shows a typical collapsible prosthetic heart valve 100. Theprosthetic heart valve 100 is designed to replace the function of anative aortic valve of a patient. Examples of collapsible prostheticheart valves are described in International Patent ApplicationPublication No. WO/2009/042196; U.S. Pat. No. 7,018,406; and U.S. Pat.No. 7,329,278, the disclosures of all of which are hereby incorporatedherein by reference. As discussed in detail below, the prosthetic heartvalve has an expanded condition and a collapsed condition. Although theinvention is described herein as applied to a prosthetic heart valve forreplacing a native aortic valve, the invention is not so limited, andmay be applied to prosthetic valves for replacing other types of cardiacvalves.

The prosthetic heart valve 100 includes a stent or frame 102, which maybe wholly or partly formed of any biocompatible material, such asmetals, synthetic polymers, or biopolymers capable of functioning as astent. Suitable biopolymers include, but are not limited to, elastin,and mixtures or composites thereof. Suitable metals include, but are notlimited to, cobalt, titanium, nickel, chromium, stainless steel, andalloys thereof, including nitinol. Suitable synthetic polymers for useas a stent include, but are not limited to, thermoplastics, such aspolyolefins, polyesters, polyamides, polysulfones, acrylics,polyacrylonitriles, polyetheretherketone (PEEK), and polyaramides. Thestent 102 may have an annulus section 110, an aortic section (notshown), and an intermediate section (not shown) disposed between theannulus and aortic sections. Each of the annulus section 110, theintermediate section, and the aortic section of the stent 102 includes aplurality of cells 112 connected to one another around the stent. Theannulus section 110, the intermediate section, and the aortic section ofthe stent 102 may include one or more annular rows of cells 112connected to one another. For instance, the annulus section 110 may havetwo annular rows of cells 112. When the prosthetic heart valve 100 is inthe expanded condition, each cell 112 may be substantially diamondshaped. Regardless of its shape, each cell 112 is formed by a pluralityof struts 114. For example, a cell 112 may be formed by four struts 114.

The stent 102 may include commissure features or commissure posts (notshown) connecting at least two cells 112 in the longitudinal directionof the stent 102. The commissure features may include eyelets thatfacilitate the suturing of a valve assembly 104 to the sent 102.

The prosthetic heart valve 100 also includes a valve assembly 104attached inside the annulus section 110 of the stent 102. United StatesPatent Application Publication No. 2008/0228264, filed Mar. 12, 2007,and United States Patent Application Publication No. 2008/0147179, filedDec. 19, 2007, the entire disclosures of both of which are herebyincorporated herein by reference, describe suitable valve assemblies.The valve assembly 104 may be wholly or partly formed of any suitablebiological material, fabric or a polymer. Examples of biologicalmaterials suitable for the valve assembly 104 include, but are notlimited to, porcine or bovine pericardial tissue. Examples of polymerssuitable for the valve assembly 104 include, but are not limited to,polyurethane and polyester.

The valve assembly 104 may include a cuff 106 disposed on the luminalsurface of annulus section 110, on the abluminal surface of the annulussection, or on both surfaces, and the cuff may cover all or part ofeither or both of the luminal and abluminal surfaces of the annulussection. FIG. 1A shows cuff 106 disposed on the luminal surface ofannulus section 110 so as to cover part of the annulus section whileleaving another part thereof uncovered. In addition to the materials forforming valve assembly 104 noted above, the cuff 106 and/or any of thesutures described herein may include ultra-high-molecular-weightpolyethylene. The valve assembly 104 may further include a plurality ofleaflets 108 which collectively function as a one-way valve.

The cuff 106 of the prosthetic heart valve 100 of FIG. 1A tends toexperience relatively high strain and/or stress at certain locations. Insuch heart valves 100, the pressure of blood that leaflets 108 keep fromflowing into the heart may subject leaflets 108 to a load in thedirection indicated by arrow L, shown in FIG. 1B. This load may causehigh stress and/or strain on the cuff and/or leaflets. Moreover, atypical load may cause wear over time. To manage the increased stressand strain on the cuff 106, some conventional heart valves 100 have madethe cuff thicker. However, thicker cuffs generally lead to a largerheart valve that is more difficult to deliver and implant.

One method of redistributing the load has been to attach the leaflets tothe struts. Alternatively, it may be advantageous to attach the leafletssubstantially entirely to the cuff and not to the struts. In certainprocedures, collapsible valves may be implanted in a native valveannulus without first resecting the native valve leaflets. Additionally,other patients may have uneven calcification, bi-cuspid disease, and/orvalve insufficiency.

To reduce adverse events, (e.g., (1) perivalvular leakage (PV leak), (2)valve migration, (3) mitral valve impingement, (4) conduction systemdisruption, (5) coronary blockage, etc.) adequate sealing and anchoringwithout excessive radial force may be advantageous. Embodiments of thepresent invention which attach the leaflets mainly to the cuff are ableto achieve better coaptation of the leaflets, reducing the risk ofleakage.

Moreover, the annulus section of the prosthetic valve may have agenerally regular cylindrical shape by which is meant that the structurehas a generally circular cross-section with a substantially constantdiameter along its length. When placed in the annulus of a native heartvalve, such as, for example, the tricuspid aortic valve, and expanded, asubstantially fluid-tight fit should result. However, the native valveannulus may not be circular, and, in fact, may vary from patient topatient, as may the shape of the aortic sinus or aorta, the angle of thejunction between the valve annulus and the aortic sinus, and other localanatomical features. When a prosthetic valve is deployed and expanded,it is advantageous that it accommodates these anatomical variations inorder to function properly. This may result in distortion of the shapeof the stent and/or valve assembly, and the repositioning of leafletsrelative to one another, which can affect the coaptation of theseleaflets.

As the stent of a collapsible prosthetic heart valve distorts duringimplantation, during beating of the heart, or because of irregularitiesin the patient's anatomy or the condition of the native valve, suchdistortion may be translated to the valve assembly, such that not all ofthe valve leaflets meet to form effective coaptation junctions. This canresult in leakage or regurgitation and other inefficiencies which canreduce cardiac performance. Moreover, if the prosthetic valve is notplaced optimally and the valve leaflets are not coapting as intended,other long term effects, such as uneven wear of the individual leafletsor increased stress on the cuff and/or stent, may be postulated.

Prosthetic valves in accordance with certain aspects of the presentinvention, however, can function properly notwithstanding the distortionof the stent and/or valve assembly because the leaflets aresubstantially attached to the cuff and not to the stent. Without wishingto be held to any particular theory, it is believed that a valve designhaving leaflets mostly sewn to the cuff may be better able to adjust toless than perfect annulus geometry. Such leaflet-cuff arrangements maybe more insulated from imperfect geometry-induced stresses on the strutsthan those arrangements having the leaflets completely or predominantlysewn to the stent. Thus, the possibility of uneven wear due toanatomical variations is greatly reduced by attaching the leafletsentirely or predominantly to the cuff.

Moreover, by sewing the leaflets to the cuff and not to the struts,greater flexibility is afforded in positioning the leaflets and invarying the height, width and shape of the leaflets. Specifically,because the leaflets in conventional heart valves are attached to thestruts, the leaflet shape and positioning is limited by the location ofthe struts. In contrast, suturing patterns may be varied with greaterbenefits when the leaflets are attached predominantly to the cuff.

Having outlined some of the benefits of a leaflet-cuff attachment, thefeatures of this embodiment will be described in connection with theprosthetic heart valve 300 shown in FIGS. 2A-5. It will also be notedthat while the inventions herein described are predominately discussedin terms of a tricuspid valve and a stent having a shape as illustratedin FIGS. 2A-5, the valve could be a bicuspid valve, such as the mitralvalve, or include more than three leaflets, and the stent could havedifferent shapes, such as a flared or conical annulus section, aless-bulbous aortic section, and the like, and a differently shapedintermediate section.

In attaching the plurality of leaflets, each leaflet 308 may be firstattached to the stent 302 by suturing through the eyelets of commissurefeatures 316. Additional examples of leaflet-commissure featureattachments are disclosed in U.S. patent application Ser. No.13/216,124, entitled “Leaflet Suturing to Commissure Points forProsthetic Heart Valve”, filed on Aug. 23, 2011, the disclosure of whichis hereby incorporated by reference as if fully set forth herein. Inaddition to the commissure features 316, the plurality of leaflets maybe attached to the cuff 306 as described below.

FIGS. 2A, 2B and 3 illustrate one such embodiment in which the leaflets308 have been attached by suturing substantially entirely to the cuff306. In the illustrated embodiment, the leaflets 308 are coupled to thecuff 306 after they have been attached to the commissure features 316.It will be understood, however, that the order of attachment may bechanged or varied as necessary by those skilled in the art.

FIGS. 2A and 2B illustrate a cuff 306 and one or more leaflets 308. Eachleaflet 308 includes a proximal end 352 for attachment to the cuff 306and a free distal end 354 for coapting with the other leaflets to form aclosed valve. As seen in FIG. 2A, each leaflet 308 may be folded uponitself at the proximal end 352 to form a belly flap 356 for attachingthe leaflet to the cuff 306. The belly flap 356 may be formed by foldingthe proximal end of the leaflet 308 once over itself toward the cuff 306so that the belly flap is disposed between a portion of the leaflet andthe cuff. The width x of the belly flap 356 between fold line 356 a andfree edge 356 b may vary from valve to valve, and also within a valve.For example, the belly flap 356 may have a width x between about 0.1 mmand about 2.0 mm. Variants of the belly flap 356 are also contemplatedherein. For example, the belly flap 356 may be formed by folding theleaflet 308 more than once (e.g., twice, thrice or more). Additionally,the belly flap 356 may be formed along only a portion of the proximalend of the leaflet 308 if the entire proximal end will not be sutured tothe cuff 306. Still further, the belly flap 356 may be formed by foldingthe proximal end of the leaflet 308 away from the cuff 306, rather thantoward the cuff as described above.

After folding each leaflet 308 to form a belly flap 356, the leaflets308 may be attached to the cuff 306 in accordance with the attachmentpattern shown in FIG. 3. For the purpose of clarity, the leaflet-cuffattachment pattern will be described with reference to FIG. 3 withoutshowing a belly flap. It will be understood, however, that a belly flapas described above and shown in FIGS. 2A and 2B may be disposed eitheron the inner or luminal side of the leaflet 308 or between the leafletand the cuff 306.

The prosthetic heart valve 300 of FIG. 3 includes a stent or frame 302having an annulus section 310 and an aortic section (not shown). Each ofthe annulus section 310 and the aortic section of the stent 302 includesa plurality of cells 312 connected to one another around thecircumference of the stent. The annulus section 310 and the aorticsection of the stent 302 may include one or more annular rows of cells312 connected to one another. For instance, the annulus section 310 mayhave two annular rows of cells 312. When the prosthetic heart valve 300is in the expanded condition, each cell 312 may be substantially diamondshaped. Regardless of its shape, each cell 312 is formed by a pluralityof struts 314. For example, a cell 312 may be formed by four struts 314.

The stent 302 may include commissure features 316 connecting at leasttwo cells 312 in the longitudinal direction of the stent. The commissurefeatures 316 may include eyelets for facilitating the suturing of avalve assembly 304 to the stent 302.

A cuff 306 may be disposed on the luminal surface of annulus section310, on the abluminal surface of the annulus section, or on bothsurfaces, and the cuff may cover all or part of either or both of theluminal and abluminal surfaces of the annulus section. FIG. 3 shows cuff306 disposed on the luminal surface of annulus section 310 so as tocover part of the annulus section while leaving another part thereofuncovered. In particular, the cuff 306 covers substantially all of theannulus section 310 between the proximal edge of stent 302 and thecommissure features 316, but a much lesser area of the annulus sectionbetween the commissure features. The valve assembly 304 may furtherinclude a plurality of leaflets 308 which collectively function as aone-way valve.

As shown in FIG. 3, struts 314 a, 314 b, and 314 c may be connected toone another in substantially end-to-end fashion diagonally along threecells 312, beginning with an end of the strut 314 a connected to acommissure feature 316 a and ending with an end of strut 314 c connectedto an end of strut 314 d. Struts 314 c and 314 d are part of the samecell 312 a. Struts 314 d, 314 e, and 314 f may be connected to oneanother in substantially end-to-end fashion diagonally along three cells312, beginning with an end of the strut 314 f connected to a commissurefeature 316 b and ending with the connection between an end of strut 314d and an end of strut 314 c. For the sake of completeness, cell 312 aincludes strut 314 c connected to strut 314 d at the bottom of the celland struts 314 g and 314 h connected to one another at the top of thecell, as well as to struts 314 d and 314 c, respectively.

In addition to being connected to one another around the circumferenceof stent 302, cells 312 may be connected to one another in thelongitudinal direction of the stent. Two adjacent struts, for examplestruts 314 e and 314 g, merge near the bottom of the cell beforesplitting off into two different struts. The meeting point where twostruts 314 merge or where one strut splits into two components isdefined as an ancon 320. The ancons 320 in two longitudinally adjacentrows of cells 312 may be joined by runners r.

The plurality of leaflets 308 may be attached directly to the cuff 306near struts 314 a, 314 b, 314 e, and 314 f, such as by suturing. Asshown in FIG. 3, the leaflets 308 may be attached to cuff 306 justproximally of the aforementioned struts 314 along an attachment line R.Specifically, a distance y may be maintained between the attachment lineR and the struts 314. This distance may be greater than, less than orequal to 2.0 mm, and may vary as necessary. By attaching the leaflets308 to the cuff 306 in a pattern that follows the curvature of some ofthe struts 314, stress on the cuff 306 may be reduced while maintaininga degree of flexibility.

As described above, the attachment line R includes an initial descentfrom just proximal of commissure feature 316 a and continues proximallyof struts 314 a and 314 b while substantially maintaining a distance yfrom the struts. At the proximal end of strut 314 b, the attachment lineR begins to flatten out, passing through cell 312 a, and then ascendsproximally of struts 314 e and 314 f, maintaining substantially the sameor a similar distance y from the struts, until it reaches a point justproximal of commissure feature 316 b. Between the descending seam andthe ascending seam, the attachment line may cross a pair of runners r1and r2 and form a vertex therebetween. In at least some other examples,attachment line R may pass above or below at least one of the runners r1and r2.

FIG. 4 shows runners r1 and r2 in more detail. As described above, theattachment line R generally descends from a point just proximal ofcommissure feature 316, travels proximally of struts 314 a and 314 b,crosses runner r1, changes direction and crosses runner r2, and thenascends proximally of struts 314 e and 314 f until it reaches a pointjust proximal of commissure feature 316 b.

The foregoing discussion describes the general pattern by which leaflets308 may be attached directly to cuff 306. Having generally described theattachment pattern, the following description provides one exemplarymethod of suturing the leaflets 308 to the cuff 306. As will beunderstood by those of ordinary skill in the art, the description belowis for one of many possible methods, and the distances, configurationsand arrangements described are merely exemplary and not limiting. Forexample, instead of using a single suture around the perimeter of thevalve assembly, leaflets 308 may be sutured to the cuff 306 using aplurality of sutures, staples, bioglue or any other suitable method ofattachment.

Initially, the leaflets 308 are aligned with the cuff 306 and struts 314at the desired locations, typically in the annulus section 310. The endsof the distal free edge of each leaflet 308 are then sutured to both thecuff 306 and the stent 302 through the eyelets of an adjacent pair ofcommissure features 316. The belly of the leaflets 308 may then besutured to the cuff 306 around the circumference of the heart valve 300proximally of the commissure features 316.

With reference to FIG. 3, a first leaflet 308 may be sutured to the cuff306 by first passing a suture from the abluminal side of the cuff 306 tothe luminal side of the cuff about 0.5 mm to about 2.0 mm proximally ofa first commissure feature 316 a. This location will be referred to asthe origination stitch. A suture tail segment may be maintained at theorigination stitch in order to tie to the end of the pattern afterstitching around the circumference of the cuff 306 has been completed.The leaflet 308 may then be stitched to the cuff 306 using a series ofwhip stitches. In at least some other examples, a running, orreverse-running stitch may be used instead of a whip stitch. Stitchesfrom the abluminal side to the luminal side of the heart valve 300 passthrough the cuff 306 only. Stitches from the luminal side to theabluminal side of the heart valve 300 pass through both layers of theleaflet 308 (e.g., the leaflet as well as the folded belly flap 356) andthe cuff 306. Thus, with each whip stitch the suture is passed from theabluminal side to the luminal side of the heart valve 300 through thecuff 306 only and then through both layers of the leaflet 308 and thecuff 306 from the luminal side of the valve to the abluminal sidethereof.

The stitch spacing and bite size may vary. In at least some examples,the stitch spacing and bite size may be from about 0.5 mm to about 2.0mm, and preferably is about 1.0 mm. Stitches may be approximatelyperpendicular to the leaflet edge when viewed from the side of the valve300. Beginning just proximally of commissure feature 316 a, the suturesmay travel approximately at a distance y proximally of struts 314 a and314 b, across a first runner r1, form a vertex, across a second runnerr2, and approximately at a distance y proximally of struts 314 e and 314f until reaching a point just proximal of commissure feature 316 b. Thesutures may begin at a point A about 0.5 mm to about 2.0 mm proximal ofcommissure feature 316 a, and may end at a point B about 0.5 mm to about2.0 mm proximal of commissure feature 316 b.

Thus, between the first commissure feature 316 a and the secondcommissure feature 316 b, a substantially symmetrical parabola is formedby the suture line R. This parabolic pattern may be repeated betweencommissure features 316 b and 316 c and between commissure features 316c and 316 a around the circumference of the cuff 306, ending at or nearpoint A where the suture line R began. Upon returning to point A, theconcluding tail of the suture line R may be tied to the originationstitch using a single double knot or any other suitable knot.

FIGS. 5A and 5B show a comparison between a heart valve 300 according toone embodiment of the present invention and a conventional heart valve300′. As can be seen, the heart valve 300 according to the presentinvention includes an enlarged cuff 306 that overlaps with a portion ofthe leaflets 308. In contrast, the heart valve 300′ includes no suchoverlap between the leaflets 308′ and the cuff 306′. Rather, theleaflets 308′ and cuff 306′ are attached to one another in anedge-to-edge fashion. The leaflet-cuff overlap provided by the heartvalve 300 of the present invention forms a pocket P and allows for thesuture pattern discussed above. Pocket P formed by the leaflet-cuffoverlap minimizes perivalvular leakage and acts as a tissue buffer forimproved durability. Compared to conventional devices, thisconfiguration also provides a larger buffer against fretting corrosion.Thus, by providing an enlarged cuff, the stress on the cuff may bedecreased, the durability of the cuff increased and the flexibility ofthe heart valve increased to allow for applications such as partialdeployment of the heart valve, for example, for testing.

In this manner, by attaching the leaflets 308 to the cuff 306, a host ofbenefits as enumerated above, as well as others, may be achieved.Moreover, the description above provides one method by which stress onthe cuff can be reduced. Namely, by suturing the leaflets to the cuff,maintaining the spacing between the suture line and the struts describedabove, and passing the sutures across the runners, the load on the cuffcan be partially redistributed to the struts to prevent possible wearand/or failure. Thus, the foregoing embodiment describes one method forreducing stress on the cuff at critical junctions. This method providesa solution by suturing the leaflets to the cuff without providing athicker cuff or using different materials for the cuff.

The above embodiment notwithstanding, it will be understood that theleaflets need not be coupled only (except for the commissure features)to the cuff. In other embodiments, instead of suturing the leaflets toonly the cuff, selected regions of each leaflet, or the proximal edgethereof, may be attached to an underwire disposed on or coupled to thecuff to relieve additional stress from the cuff. These embodiments willbe described in more detail with reference to FIGS. 6-11.

FIG. 6 is a partial side view of a prosthetic heart valve 600 having astent 602 and a valve assembly 604 disposed in the annulus section 610of the stent. Within the heart valve 600, leaflets 608 are attached tocuff 606 via sutures. FIG. 6 shows a potential leaflet-cuff attachmentload distribution in the valve assembly. When leaflets 608 coapt to forma closed configuration, load is transferred from the leaflet structureto the attachment points along the leaflet belly contour. As describedin the above embodiments, these attachment points coincide withattachment line R. The load distribution diagram shows that high pointloads are generated at individual sutures at certain regions L alongattachment line R. If the point loads at regions L are sufficientlyhigh, they will pull the suture through the material of the cuff 606.Repetitive wear may pull the suture through the material of cuff 606.Thus, regions L may be prone to failure. This failure may occur bytearing of the cuff 606, the leaflet 608, the sutures attaching the cuff606 to the leaflet 608 or any combination thereof.

According to the present invention, a suture underwire may be attachedto the prosthetic heart valve externally of the cuff to redistribute theload at the points at which the leaflets attach to the cuff, reducingthe risk of valve structural damage due to a break in thejoint/subassembly formed between the cuff and the leaflet attachmentline R. Without being bound to any particular theory, it is believedthat the underwire may improve cuff durability, improve valve function,reduce perivalvular leakage due to cuff billowing, achieve an optimalleaflet contour and aid in reducing the implant catheter profile.

FIG. 7A is a highly schematic view of an underwire 730 secured to a cuff706 according to an embodiment of the present invention. The underwire730 may be formed of a suture, wire, fabric, polymers, reinforcedpolymers, a metal such as nitinol, a biomaterial such as pericardialtissue, stainless steel or the like, or any combination thereof, such asa braided wire or metal-suture combination. In some examples, underwire730 may be formed of an ultra-high-molecular-weight polyethylene, suchas FORCE FIBER®. The underwire 730 may also be formed as a solid rod, atube or a wire to provide support at certain portions of the cuff 706.In one specific embodiment, the underwire 730 may be formed of a nitinolwire that is heat-set to the counter of the cuff 706. As seen in theschematic view of FIG. 7A, the underwire 730 may be attached to the cuffin a parabolic pattern complementing attachment line R. The attachmentpatterns and configurations of underwire 730 will be discussed in moredetail below. It is sufficient from this diagram and from the highlyschematic diagram of FIG. 7B to appreciate that the underwire 730 willassist in supporting the suturing between the cuff 706 and the leaflets708 by providing a reinforcement to redistribute the load between theleaflets and the cuff.

FIGS. 8, 9A and 9B describe several patterns for attaching the underwireto the cuff. Though these specific attachment patterns are describedherein, it will be understood that any of the patterns described abovewith reference to attachment line R of FIG. 3 may be used for attachingthe underwire to the cuff. The attachment line may be sutured around orthrough the underwire to provide additional support. Moreover, it willbe understood that the underwire may be attached to the cuff prior tosuturing the leaflets to the cuff. For example, the underwire may beattached to the cuff before attaching the cuff to the stent or afterattaching the cuff to the stent. Additionally, the underwire may beattached to the cuff at the same time that the leaflets are sutured tothe cuff.

In a first example, shown in FIG. 8, a prosthetic heart valve 800includes a stent 802 and a valve assembly 804 disposed in the annulussection 810 of the stent. A cuff 806 is attached to the stent 802 on theluminal side of annulus section 810. Stent 802 includes a plurality ofstruts 814 connected to one another to define open cells 812. Struts 814a, 814 b, and 814 c may be connected to one another in substantiallyend-to-end fashion diagonally along three cells 812, beginning with anend of the strut 814 a connected to a commissure feature 816 a andending with an end of strut 814 c connected to an end of strut 814 d.Struts 814 c and 814 d are part of the same cell 812 a. For the sake ofcompleteness, cell 812 a includes strut 814 c connected to strut 814 dat the bottom of the cell and struts 814 g and 814 h connected to oneanother at the top of the cell, as well as to struts 814 d and 814 c,respectively.

Underwire 830 may form a pattern around the circumference of cuff 806.As with the attachment line R described above, the pattern of underwire830 may likewise include an initial descent from just proximal ofcommissure feature 816 a and may continue proximally of struts 814 a and814 b while substantially maintaining a distance y from the struts. Atthe proximal end of strut 814 b, the pattern of underwire 830 begins toflatten out, passing through cell 812 a, and then ascends proximally ofthe next set of struts (not shown in FIG. 8), until it reaches a pointjust proximal of the next commissure feature. It should be noted thatthe underwire 830 in FIG. 8 is attached to the cuff 806 and is disposedbetween the cuff and the stent 802. With this arrangement, loads fromthe underwire 830 are distributed directly to the cuff 806 only and notto the struts 814. Additionally, the pattern of underwire 830 in theembodiment of FIG. 8 begins and ends at points proximal of thecommissure features 816 as discussed.

FIG. 9A is a side view of a second example of the attachment of anunderwire 930 to a cuff 906. The prosthetic heart valve 900 is similarto the prosthetic heart valve 800 described above, and therefore likeelements are identified by like reference numerals that begin with thenumeral “9”, instead of the numeral “8”. The manner of attachment forunderwire 930 is similar to the manner of attachment for underwire 830,with two exceptions. First, underwire 930 is attached directly tocommissure features 916 instead of ending at points proximal of thecommissure features. In addition, the underwire 930 is disposedoutwardly of stent 902 as shown in the enlarged view of FIG. 9B. Thatis, stent 902 is disposed between cuff 906 and underwire 930. Byattaching underwire 930 to the commissure features 916 and/or by passingunderwire 930 outwardly of stent 902, loads may be redistributed fromthe underwire to the stent struts 914.

It should be understood that any combination of these arrangements maybe utilized to attach the underwire 930 to the cuff 906. For example,underwire 930 may be arranged between cuff 906 and stent 902 asdescribed in FIG. 8, but also may attach to the commissure features 916as described in FIG. 9. Alternatively, underwire 930 may be arrangedoutwardly of stent 902 at select points only or may be attached toselect commissure features or no commissure features. In this manner,the load may be distributed from the underwire to the cuff and/or thestent as desired.

Having described the manner of attaching the underwire to the cuff andstent, some possible arrangements for attaching the leaflets to the cuffand underwire will now be described. Several alternatives for suchattachment are shown in FIGS. 10A-C.

FIG. 10A is a highly schematic cross-sectional view of a portion of acollapsible prosthetic heart valve 1000 according to one example of thepresent invention. Heart valve 1000 has leaflets 1008 sutured to both anunderwire 1030 and a cuff 1006. Each leaflet 1008 may be folded uponitself at its proximal end to form a belly flap 1056 for attaching theleaflet 1008 to the cuff 1006. The belly flap 1056 may take any of theconfigurations or arrangements discussed above with reference to FIG. 2Aor may not include a fold at all. The structure of heart valve 1000 asdescribed in connection with FIG. 10A may be the same for FIGS. 10B and10C.

The manner in which leaflets 1008 are attached to cuff 1006 andunderwire 1030, as in FIG. 10A, will be referred to as the “wrapped”configuration. In this wrapped configuration, leaflet 1008 is foldedupon itself to form belly flap 1056. A suture T begins from the interiorof valve 1000 and passes through the leaflet 1008, the leaflet bellyflap 1056, and the cuff 1006. The suture T then wraps around underwire1030 and is passed back toward the interior of the valve through thecuff 1006 and under the folded edge of leaflet 1008, creating a whipstitch. This stitch pattern may be repeated around the entirecircumference of valve 1000 to secure each of leaflets 1008 andunderwire 1030 to cuff 1006.

A second configuration, shown in FIG. 10B, will be referred to as the“pierced” configuration. In the pierced configuration, the suture Tbegins at the interior of valve 1000 and is passed through the leaflet1008, the belly flap 1056 and the cuff 1006. Instead of wrapping aroundunderwire 1030, the suture is pierced through underwire 1030 and passedback toward the interior of the valve through the cuff 1006 and underthe folded edge of leaflet 1008. Obviously, in this embodiment theunderwire 1030 must be formed of a material capable of receiving thesuture T therethrough. This stitch pattern may be repeated around theentire circumference of valve 1000 to secure each of leaflets 1008 andunderwire 1030 to cuff 1006.

In a third configuration, the underwire 1030 is cinched as shown in FIG.10C. The “cinched” configuration may begin in a manner similar to thewrapped configuration of FIG. 10A, with suture T passing from theinterior of the valve 1000 through leaflet 1008, belly flap 1056 andcuff 1006. Suture T may then be wrapped in a full loop around theunderwire 1030 and then passed back to the interior of the valve throughcuff 1006 and under the folded edge of leaflet 1008. It will beunderstood that this cinched configuration is not limited to a singleloop around underwire 1030, and that suture T may wrap around theunderwire 1030 any number of revolutions as desired before passing backto the interior of the valve.

In another configuration, shown in FIGS. 11A and 11B, leaflet 1008 isfolded over itself to form belly flap 1056 and a reverse-running stitchB holds belly flap 1056 to leaflet 1008 to create a thickened portion,which will then be coupled to cuff 1006. Heart valve 1000 has leaflets1008 sutured to both an underwire 1030 and a cuff 1006 as shown in FIG.11B. Specifically, a suture T passes through reverse-running stitch B,leaflet 1008, leaflet belly flap 1056, the other side of revere-runningstitch B and cuff 1006. The suture T then wraps around underwire 1030and is passed back toward the interior of the valve through the cuff1006 and under the folded edge of leaflet 1008, creating a whip stitch.This stitch pattern may be repeated around the entire circumference ofvalve 1000 to secure each of leaflets 1008 and underwire 1030 to cuff1006. Folding leaflet 1008 over itself to create a belly flap and usinga reverse-running stitch B to secure the two together produces athickened portion that provides enhanced structural integrity forattaching the leaflet to cuff 1006 and underwire 1030.

FIGS. 11C-P are highly schematic cross-sectional views of variousconfigurations for attaching underwire 1030 to cuff 1006. As will beappreciated from these figures, suture T may pass through or around anycombination of the reverse-running stitch B, leaflet 1008, belly flap1056, cuff 1006, and underwire 1030. In addition to theseconfigurations, underwire 1030 may be moved to a different location, ormultiple underwires may be utilized. For example, a second underwire1030 may be disposed between leaflet 1008 and belly flap 1056 to formthe thickened portion in addition to underwire 1030 disposed outsidecuff 1006. Underwire 1030 could also be disposed inside cuff 1006 (e.g.,between cuff 1006 and belly flap 1056) or at any other suitable positionso long as it helps redistribute load over the cuff and helps preventtearing of the cuff.

In other variations, underwire 1030 may be disposed on the outside ofthe stent struts in certain portions and on the inside of the stentstruts in other portions. Underwire 1030 may also be weaved in and outof cuff 1006, and may be attached to the commissure features to provideadditional support. Additionally, underwire 1030 need not be continuousand may be formed of discrete portions disposed around the circumferenceof the heart valve.

Though the previous configurations have shown a leaflet 1008 folded overtoward the cuff 1006 to form a belly flap 1056, it will be appreciatedthat the cuff-leaflet assembly, also referred to as a belly attachmentcontour, is not limited to this configuration. In other examples, thecuff-leaflet assembly may include a leaflet that is folded away fromcuff 1006 to form a belly flap 1056 on the side of the leaflet 1008opposite the cuff. Additionally, leaflet 1008 of the cuff-leafletassembly need not form a two-layered belly flap 1056 at all but may layflat against cuff 1006. It is also contemplated that cuff 1006 itselfmay be folded over and that multiple reverse-running stitches may beutilized instead of a single stitch as described above.

As shown in FIG. 12, in another embodiment leaflet 1208 is folded alongonly a part of its belly contour. Leaflet 1208 extends between proximalend 1202 and distal end 1204 and includes a belly 1230 having a freeedge 1210 stretching between attachment regions 1212, which couple tothe commissure features of a stent. A substantially parabolic bellycontour 1214 is formed between attachment regions 1212 on the edge ofleaflet 1208 opposite free edge 1210. Portions of belly contour 1214 arefolded over to form two-layered folded portions 1220. Folded portions1220 may be formed with any length f1. In one example, folded portions1220 each include about ¼ to about ⅓ of the length of belly contour1214. In some examples, the length t1 of each folded portion 1220 isbetween about 4 mm and about 8 mm, and may be about 6 mm. Foldedportions 1220 may include the end of belly contour 1214 that are closestto attachment regions 1212. Thus, the portion of belly contour 1214between folded portions 1220 may remain substantially flat. By creatingan unfolded region spaced from the end of belly contour 1214, the bulkof the leaflet may be decreased. To reinforce the belly 1230 of leaflet1208, which will be attached to a cuff, reverse-running stitch B2 may beformed a distance f2 from belly contour 1214 and may follow thecurvature of the belly contour. As stitch B2 extends through foldedportions 1220 it may secure together the two layers forming foldedportions 1220. Reverse-running stitch B2 may terminate prior to reachingfree edge 1210 so as not to affect the coaptation of free edge 1210 withthe free edges of the other leaflets, which collectively form the valveassembly. Thus, reverse-running stitch B2 may be spaced from free edge1210 by a distance f3. In at least some embodiments, distance f3 may bebetween about 0.5 and about 5 mm.

A leaflet having an unfolded belly such as that shown in FIG. 12 may becoupled to a cuff in a variety of configurations. FIGS. 13A-H are highlyschematic cross-sectional views of some permutations for attaching anunderwire 1330 to a cuff 1306 having an unfolded belly. As will beappreciated from these figures, sutures T2A-H may pass through or aroundany combination of reverse-running stitches B2, leaflet 1308, underwire1330, and cuff 1306.

In FIG. 13A, suture T2A passes, through inner reverse-running stitchB2I, leaflet 1308, outer reverse-running stitch B2O and cuff 1306, andfinally wraps around underwire 1330 before passing through cuff 1306 asecond time and under the edge of leaflet 1308. Thus, in thisconfiguration, suture T2A passes through both inner reverse-runningstitch B2I and outer reverse-running stitch B2O and wraps aroundunderwire 1330.

In FIG. 13B, suture T2B passes, through inner reverse-running stitch B2Iand leaflet 1308, above outer reverse-running stitch B2O, and throughcuff 1306, and finally wraps around underwire 1330 before passingthrough cuff 1306 a second time and under the edge of leaflet 1308.Thus, in this configuration, suture T2B passes through only innerreverse-running stitch B2I and wraps around both outer reverse-runningstitch B2O and underwire 1330.

FIG. 13C show a configuration similar to that of FIG. 13B except thatsuture T2C passes under outer reverse-running stitch B2O instead ofabove it. Thus, in this configuration, suture T2C passes through onlyinner reverse-running stitch B2I and wraps around only underwire 1330.

In FIG. 13D, suture T2D first passes inwardly through leaflet 1308,around inner reverse-running stitch B2I and outwardly through leaflet1308, under outer reverse-running stitch B2O and through cuff 1306, andfinally wraps around underwire 1330 before passing through cuff 1306 asecond time. Thus, in this configuration, suture T2D does not passthrough any reverse-running stitches, wraps around only innerreverse-running stitch B2I and underwire 1330, and passes throughleaflet 1308 twice.

In FIG. 13E, suture T2E passes inwardly through leaflet 1308, aroundinner reverse-running stitch B2I and outwardly through leaflet 1308,through outer reverse-running stitch B2O and cuff 1306, and finallywraps around underwire 1330 before passing through cuff 1306 a secondtime. Thus, in this configuration, suture T2E wraps around both innerreverse-running stitch B2I and underwire 1330 and passes through outerreverse-running stitch B2O.

In FIG. 13F, suture T2F passes inwardly through leaflet 1308, aboveinner reverse-running stitch B2I outwardly through leaflet 1308, aboveouter reverse-running stitch B2O and through cuff 1306, and finallywraps around underwire 1330 before passing through cuff 1306 a secondtime. Thus, in this configuration, suture T2F wraps around all of innerreverse-running stitch B2I, outer reverse-running stitch B2O andunderwire 1330.

In FIG. 13G, suture T2G passes inwardly through leaflet 1308, throughinner reverse-running stitch B2I, outwardly through leaflet 1308, aboveouter reverse-running stitch B2O and through cuff 1306, and finallywraps around underwire 1330 passing through cuff 1306 a second time.Thus, in this configuration, suture T2G passes through innerreverse-running stitch B2I, and wraps around both outer reverse-runningstitch B2O and underwire 1330.

In FIG. 13H, suture T2H passes inwardly through leaflet 1308, throughinner reverse-running stitch B2I, outwardly through leaflet 1308,through outer reverse-running stitch B2O, cuff 1306, and underwire 1330,and returns by passing through cuff 1306 a second time. Thus, in thisconfiguration, suture T2H passes through all of inner reverse-runningstitch B2I, outer reverse-running stitch B2O and underwire 1330, as wellas twice through each of cuff 1306 and leaflet 1308.

In FIG. 13I, suture T2I passes inwardly through leaflet 1308, underinner reverse-running stitch B2I, outwardly through leaflet 1308, underouter reverse-running stitch B2O and through cuff 1306, and finallywraps around underwire 1330 before passing through cuff 1306 a secondtime. In this configuration, suture T2I wraps around only underwire1330.

In FIG. 13J, suture T2J passes inwardly through leaflet 1308, underinner reverse-running stitch B2I, outwardly through leaflet 1308,through outer reverse-running stitch B2O and cuff 1306, and finallywraps around underwire 1330 before passing through cuff 1306 a secondtime. In this configuration, suture T2J wraps around only underwire 1330and passes through outer reverse-running stitch B2O.

In FIG. 13K, suture T2K passes inwardly through leaflet 1308, underinner reverse-running stitch B2I, outwardly through leaflet 1308, overouter reverse-running stitch B2O and through cuff 1306, and finallywraps around underwire 1330 before passing through cuff 1306 a secondtime. In this configuration, suture T2K wraps around underwire 1330 andouter reverse-running stitch B2O.

In addition to these configurations, underwire 1330 may be moved to adifferent location, or multiple underwires may be utilized. Moreover,multiple sutures T2 may be used to couple any combination of cuff 1306,leaflet 1308, reverse-running stitches B2 and underwire 1330 and may bepassed through or around any combination of these elements.

FIG. 14 shows another embodiment of a leaflet 1408 that is folded alongonly a part of its belly contour. Leaflet 1408 extends between proximalend 1402 and distal end 1404 and includes a belly 1430 having a freeedge 1410 stretching between attachment regions 1412, which couple tocommissure features as described above. A substantially parabolic bellycontour 1414 is formed between attachment regions 1412 on the edge ofleaflet 1408 opposite free edge 1410. Two portions of belly contour 1414are folded over to form two-layered folded portions 1420. To reinforcebelly 1430, which will be attached to a cuff, a reverse-running stitchB3 may be formed with two segments, B3 a and B3 b that follows thecurvature of belly contour 1414 at a spaced distance therefrom in amanner similar to that described with reference to FIG. 12.Reverse-running stitch B3 is formed with a different pattern than thatshown in FIG. 12. Specifically, the first segment B3 a ofreverse-running stitch B3 has a recurring, substantially diamond-shapedpattern along the belly contour of the leaflet. The selected patternaffects load transfer properties, ease of assembly, and bulkiness. Inthis case, the pattern of the first segment B3 a of reverse-runningstitch B3 may provide a larger area to suture into instead of goingthrough/around a single line of reverse-running stitch.

The first segment B3 a of reverse-running stitch B3 may terminate priorto reaching folded portions 1420, the layers of which may be securedtogether by a curved second segment B3 b or reverse-running stitch B3.Alternatively, first segment B3 a may extend through folded portion1420. Additionally, reverse-running stitch B3 may terminate prior toreaching free edge 1410 so as not to affect the coaptation of free edge1410 with the free edges of the other leaflets, which collectively formthe valve assembly.

FIG. 15 shows another embodiment of a leaflet 1508 that is folded alongonly part of its belly contour. Leaflet 1508 extends between proximalend 1502 and distal end 1504 and includes a belly 1530 having a freeedge 1510 stretching between attachment regions 1512, which couple tocommissure features as described above. A substantially parabolic bellycontour 1514 is formed between attachment regions 1512 on the edge ofleaflet 1508 opposite free edge 1510. Portions of belly contour 1514 arefolded over to form two-layered folded portions 1520. To reinforce belly1530, which will be attached to a cuff, a reverse-running stitch B4 maybe formed with two complementary second segments, B4 a and Bob thatfollow the curvature of belly contour 1514 at a spaced distancetherefrom. In this embodiment, segments B4 a and Bob of reverse-runningstitch B4 are not attached to one another.

First segment B4 a may be substantially parabolic and may terminateprior to reaching folded portions 1520. Second segment Bob may followthe contour of first segment Bob at a spaced distance therefrom todefine a coupling area 1540 therebetween for suturing leaflet 1508 to acuff. Second segment Bob may extend through folded portions 1520 tosecure the two layers of each folded portion together. In either case,reverse-running stitch B4 may terminate prior to reaching free edge 1510so as not to affect the coaptation of free edge 1510 with the free edgesof the other leaflets, which collectively form the valve assembly.

FIG. 16 shows another embodiment that is similar to that of FIG. 15,except for the pattern of reverse-running stitch B5. Leaflet 1608extends between proximal end 1602 and distal end 1604 and includes abelly 1630 having a free edge 1610 stretching between attachment regions1612, and a substantially parabolic belly contour 1614 formed betweenattachment regions 1612 on the edge of leaflet 1608 opposite free edge1610. Reverse-running stitch B5 may be formed with two complementarysegments, B5 a and B5 b that follow the curvature of belly contour 1614at a spaced distance therefrom. Segments B5 a and B5 b ofreverse-running stitch B5 are attached to one another by segments B5 c,thereby creating a number of coupling rectangles 1650 for receivingsutures to couple leaflet 1608 to a cuff.

First segment B5 a may be substantially parabolic and may terminateprior to reaching folded portion 1620. Second segment B5 b may followthe contour of first segment B5 b at a spaced distance therefrom, andmay extend through folded portions 1620 to secure the two layers of eachfolded portion together. Suture 1670 may couple leaflet 1608 to a cuffthrough coupling rectangles 1650. Specifically, suture 1670 may bepassed through the perimeter of a coupling rectangle 1650. It may beadvantageous to pierce the perimeter of coupling rectangle 1650 withoutpiercing through the interior of coupling rectangle 1650 more than onceand without piercing the belly 1630 in regions outside of couplingrectangle 1650.

FIG. 17 shows another embodiment that is similar to that of FIG. 16,except for the pattern of reverse-running stitch B6. Leaflet 1708extends between proximal end 1702 and distal end 1704 and includes abelly 1730 having a free edge 1710 stretching between attachment regions1712, and a substantially parabolic belly contour 1714 formed betweenattachment regions 1712 on the edge of leaflet 1708 opposite free edge1710. Reverse-running stitch B6 may be formed with two segments, B6 aand B6 b that follow the curvature of belly contour 1714 at a spaceddistance therefrom.

First segment B6 a of reverse-running stitch B6 may include a recurringtriangular pattern for accepting a suture therethrough. Suture 1770 maycouple leaflet 1708 to a cuff through coupling triangles 1750.Specifically, suture 1770 may be passed through the perimeter of acoupling triangle 1750. It may be advantageous to pierce the perimeterof coupling triangle 1750 without piercing through the interior ofcoupling triangle 1750 more than once and without piercing the belly1730 in regions outside of coupling triangle 1750.

In operation, any of the embodiments of the prosthetic heart valvedescribed above may be used to replace a native heart valve, such as theaortic valve. The prosthetic heart valve may be delivered to the desiredsite (e.g., near a native aortic annulus) using any suitable deliverydevice. During delivery, the prosthetic heart valve is disposed insidethe delivery device in the collapsed condition. The delivery device maybe introduced into a patient using a transfemoral, transapical,transseptal, transradial, transaortic, transsubclavian or otherpercutaneous approach. Once the delivery device has reached the targetsite, the user may deploy the prosthetic heart valve. Upon deployment,the prosthetic heart valve expands into secure engagement within thenative aortic annulus. When the prosthetic heart valve has been properlypositioned inside the heart, it works as a one-way valve, allowing bloodto flow in one direction and preventing blood from flowing in theopposite direction.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. For example, in some embodiments, the underwire mayinclude certain anchoring features, such as barbs for anchoring theheart valve or for valve-in-valve implantation. In at least some otherembodiments, the underwire may include a surface finish or be doped withdrugs or other material to ensure tissue ingrowth and sealing. Moreover,while the preceding discussion has provided examples by way of foldedleaflets, it will be understood that the leaflet need not be folded andthat the heart valve may instead include a belly attachment contourhaving an unfolded leaflet instead of a folded leaflet. It is thereforeto be understood that numerous modifications may be made to theillustrative embodiments and that other arrangements may be devisedwithout departing from the spirit and scope of the present invention asdefined by the appended claims.

In some embodiments, a prosthetic heart valve includes a stent having acollapsed condition and an expanded condition, the stent having aproximal end, a distal end and a plurality of commissure features. Theheart valve further includes a valve assembly secured to the stent, thevalve assembly including a cuff and a plurality of leaflets, each of theleaflets having a free edge having a first end and a second end, and asecond edge secured to the cuff, the second edge having a first end, asecond end, a first folded portion adjacent the first end, a secondfolded portion adjacent the second end, and an unfolded portion betweenthe first and second folded portions. The first and second foldedportions couple the leaflet to ones of the commissure features.

In some examples, a reinforcement may be disposed along the unfoldedportion of each of the leaflets. The reinforcement may include areverse-running stitch. The reverse-running stitch may be formed in asubstantially parabolic pattern that follows the curvature of theunfolded portion. The reverse-running stitch may include multiplesegments and at least one of the segments extends over one of the firstfolded portion and the second folded portion. The reverse-running stitchmay include a recurring diamond-shaped pattern. The reverse-runningstitch may include a recurring rectangular pattern. The reverse-runningstitch may include a recurring triangular pattern. The reverse-runningstitch may be spaced away from the free edge of the leaflet. Thereverse-running stitch may be spaced away from the free edge of theleaflet. The reverse-running stitch may include two complementaryparabolic curves defining a coupling region therebetween for receivingsutures. A reinforcing underwire may be coupled to the cuff. Theunderwire may form a repeating parabolic pattern about the circumferenceof the cuff.

In some embodiments, a prosthetic valve assembly includes asubstantially cylindrical cuff, a plurality of leaflets disposed insidethe cuff, a reverse-running stitch coupled to unfolded portions of eachof the leaflets, the reverse-running stitch having an outer partdisposed between the cuff and each of the leaflets and an inner partdisposed on an opposite side of each of the leaflets and a suture forcoupling the cuff to each of the leaflets.

In some examples, an underwire may be disposed on an abluminal surfaceof the cuff. The suture may pass through each of the cuff, ones of theleaflets, the inner part of the reverse-running stitch, the outer partof the reverse-running stitch and the underwire. The suture may passover the inner part of the reverse-running stitch, the outer part of thereverse-running stitch and the underwire, and passes through each of thecuff and ones of the leaflets. The suture may wrap around the underwire.The suture may pass through one of the inner part and the outer part ofthe reverse-running stitch. The suture may pass over one of the innerpart and the outer part of the reverse-running stitch.

It will be appreciated that the various dependent claims and thefeatures set forth therein can be combined in different ways thanpresented in the initial claims. It will also be appreciated that thefeatures described in connection with individual embodiments may beshared with others of the described embodiments.

1. A prosthetic heart valve, comprising: a stent having a collapsedcondition and an expanded condition, the stent having a proximal end, adistal end and a plurality of commissure features; and a valve assemblysecured to the stent, the valve assembly including a cuff and aplurality of leaflets, each of the leaflets having a free edge having afirst end and a second end, and a second edge secured to the cuff, thesecond edge having a first end, a second end, a first folded portionadjacent the first end, a second folded portion adjacent the second end,and an unfolded portion between the first and second folded portions,the first and second folded portions coupling the leaflet to ones of thecommissure features.
 2. The prosthetic heart valve according to claim 1,further comprising a reinforcement disposed along the unfolded portionof each of the leaflets.
 3. The prosthetic heart valve according toclaim 2, wherein the reinforcement comprises a reverse-running stitch.4. The prosthetic heart valve according to claim 3, wherein thereverse-running stitch is formed in a substantially parabolic patternthat follows the curvature of the unfolded portion.
 5. The prostheticheart valve according to claim 3, wherein the reverse-running stitchcomprises multiple segments and at least one of the segments extendsover one of the first folded portion and the second folded portion. 6.The prosthetic heart valve according to claim 3, wherein thereverse-running stitch comprises a recurring diamond-shaped pattern. 7.The prosthetic heart valve according to claim 3, wherein thereverse-running stitch comprises a recurring rectangular pattern.
 8. Theprosthetic heart valve according to claim 3, wherein the reverse-runningstitch comprises a recurring triangular pattern.
 9. The prosthetic heartvalve according to claim 3, wherein the reverse-running stitch is spacedaway from the free edge of the leaflet.
 10. The prosthetic heart valveaccording to claim 3, wherein the reverse-running stitch is spaced awayfrom the free edge of the leaflet.
 11. The prosthetic heart valveaccording to claim 5, wherein the reverse-running stitch comprises twocomplementary parabolic curves defining a coupling region therebetweenfor receiving sutures.
 12. The prosthetic heart valve according to claim1, further comprising a reinforcing underwire coupled to the cuff. 13.The prosthetic heart valve according to claim 12, wherein the underwireforms a repeating parabolic pattern about the circumference of the cuff.14. A prosthetic valve assembly, comprising: a substantially cylindricalcuff; a plurality of leaflets disposed inside the cuff; areverse-running stitch coupled to unfolded portions of each of theleaflets, the reverse-running stitch having an outer part disposedbetween the cuff and each of the leaflets and an inner part disposed onan opposite side of each of the leaflets; and a suture for coupling thecuff to each of the leaflets.
 15. The valve assembly according to claim14, further comprising an underwire disposed on an abluminal surface ofthe cuff.
 16. The valve assembly according to claim 15, wherein thesuture passes through each of the cuff, ones of the leaflets, the innerpart of the reverse-running stitch, the outer part of thereverse-running stitch and the underwire.
 17. The valve assemblyaccording to claim 15, wherein the suture passes over the inner part ofthe reverse-running stitch, the outer part of the reverse-running stitchand the underwire, and passes through each of the cuff and ones of theleaflets.
 18. The valve assembly according to claim 15, wherein thesuture wraps around the underwire.
 19. The valve assembly according toclaim 15, wherein the suture passes through one of the inner part andthe outer part of the reverse-running stitch.
 20. The valve assemblyaccording to claim 15, wherein the suture passes over one of the innerpart and the outer part of the reverse-running stitch.